aircowboy

My Feedback: (10)

Here is a picture of my poster board plane I built. I am new to R/C planes and have not had a successful landing yet! I destroyed my Sig Kadet 40 and decided to purchase a Duraplane 40 Trainer. I finished building the Duraplane and have not flown it yet. I decided that the Duraplane was not indestructable enough for me so I built a Trainer out of foam posterboard I bought at Office Max. I have only about $35 into this plane(not counting the radio and engine). I based the demensions on my crashed Sig Kadet and the weight is also similar. I dont know how to balance the plane though and any help would be greatly appreciated. Any other comments are also welcome. I am hoping this plane will fly nice and slow so I have a chance to hone my skills for my duraplane.

the_knack

My Duraplane nosed in at half throttle from about 200 ft. Patched up the wing, put on a new prop and was ready to fly again next day. I'll take more abuse than you think. Get yourself an instructor if there's one available and you'll be flying like a pro in no time. Good Luck my friend!
Danny

BMatthews

It should balance at the same place as the original Kadet if you followed the layout the same. If you can't find the info then 28 to 30% of the wing chord back from the leading edge is a safe starting point.

The model looks good from the picture. But things that a new builder like yourself may forget need some checking;

• Check the angle between the flat wing bottom and the stabilizer. The stbilizer should be parrall or negative (leading edge down) by a degree or two. If it's positive then fix it so it is negative. 1/32's count here close enough usually isnt'
• Wing alignment. Check the wing to be sure it's centered excactly on the fuselage and put some marks so you can set it accruatley later. Your eyeball isn't good enough for this.
• Check that the wing is sitting square to the model centerline. After you check for centering as above check for alignment. Put a pin into the model just at the leading edge of the fin and measure to the point at the wingtip trailing edge. The measurement should be the same from side to side if the wing is sitting square to the model.
• Once you've got the wing sitting centered and square on the model use something to mark it so you can reposition it when it gets bumped. Or better yet glue some split dowels on the bottom next to the fuselage so it HAS to sit in the same spot each time you put it on.
• Check the fin and rudder for true alignment to the wing. They sould be perpendicular to the leading edge when looking down from the top of the model. A good yardstick held along the fin and rudder and a square at the wing leading edge should answer this quick. If it's out a little you can compensate with some rudder trim. If it's more than about 1/16 along the fin and rudder I'd redo it.

Good luck and congrats on rolling your own. Hope the alignment stuff helped.

PS: I had the misfortune to fly a Duraplane one time when helping a new student. They ARE tough and that's a good thing becuase they are so heavy and fly so badly that they NEED to be tough. Sorry to all you Duraplane lovers but I like my models to fly instead of stagger. I honestly feel they actually make it harder to learn to fly landings and takeoffs because they are always on the verge of a nasty stall. I was not impressed to say the least.......

aircowboy

My Feedback: (10)

Thanks very much BMatthews, That information will help alot. Careful measurements were taken during construction of this plane, so only minor adjustments should be needed. I am definitely going to rig something up on the main wing so that it sits in the same place every time. Just got the landing gear today and it should be ready for flight soon. Still need to hook up the servos and throttle cable, and figure out how to work the ailerons. I think I will mount the servo in the top of the wing like the duraplane. I do still have the wing from the crashed Kadet, but it needs some repair before I strap it on to the poster board plane. Thanks again!

banktoturn

aircowboy,

In my opinion, the toughness of your plane is far from the most important ingredient in learning to fly. Perhaps they are better now, but my Duraplane did not fly well, and was not a good plane to use as a trainer. The important thing about a trainer is how it flies, not how it crashes. Get an instructor, and use a plane that flies well. For a trainer, flying well means relatively slowly and with plenty of stability. Almost all of the planes sold as 'trainers' fit this bill. In my opinion, the so called 'trainers' that are the least likely to fly well are the ones that are intended to be indestructable. Did you have an instructor when you were flying your Kadet? After I made the switch from my Duraplane to a Goldberg Eagle, and found an instructor, I've only had a couple close calls & rough landings, and it doesn't have a scratch on it, apart from the dings it has picked up in the car and the garage.

The plane in your picture looks like a classic trainer to me. If the dimensions and weight are similar to a Kadet, it should do OK. The incidence of the wing and horizontal stabilizer would be the most sensitive things, as BMatthews suggests. My only other suggestion is that a trainer should have ailerons, if you haven't ruled it out by the way you built the wing. This is not mandatory, but I think it is the best way to learn. Above all, get an instructor if at all possible.

Good luck,

banktoturn

aircowboy

My Feedback: (10)

I have added ailerons since the photo was taken. I weighed the plane with all the running gear and it weighs in at 5 lbs., similar to other trainer kits. I have checked the horizontal stabilizer and it is looking good, with just a VERY slight downward pitch to the rear(similar to my duraplane). Seems like alot of poeple have tried the Duraplane and didnt like it. It seems a little heavy to me, but I will try it and see.

Panzlflyer

My Feedback: (15)

What you have built is very similar to the SPAD designs.
Search the Spad forum or go to Spadtothebone.com theres plenty of info there.

Scott_nra

Hey I think that thing is COOL! I am scratch building a foamie park flier sized sailplane now and using the same foam board for the flat bottom of the wing. I'm wondering myself how strong it will be.

Have you flown it yet?

aircowboy

My Feedback: (10)

Because I live in upstate NY and there is 2feet+ of snow on the ground, I havent flown it yet. I was test firing the motor the other day and accidently bumped into the wall while carrying it and put a crease in the hor. stabilizer. Now the stabilizer bends freely and I have to develope something to strengthen it. I guess I should have laminated these surfaces with balsa sheeting. The rest of the plane is very strong and if we get a warm day and then the snow freezes creating a hard crust, then I wil try to fly it. I have rebuilt my Sig Kadet and want to take the gear from this plane and put it in that one, but I want to see this thing fly first!

Scott_nra

Neat! I decided on using the poster board for a new scratch built Sail plane I making but after cutting the piece for the bottom of the wing I juged it too heavy and went back to the foam meat trays for material.

I hope to build a bird out of the blue fan fold fold stuff soon to try that out. You can get a huge pile of it for about $20!

aircowboy

My Feedback: (10)

What is this blue fan fold fold stuff? And where do you get it? I never thought of using foam meat trays! That stuff is super light! What do you make the fuselage out of?

Scott_nra

The blue fan fold foam is available at the home centers in big bales. Right now it is bigger than I can store for about $20 or so! You make piles of planes out of it. It is a bit flimsy by itself so you use it to fabricate built up fuse or wing and use carbon fiber (Arrow shafts are great and cheap too) or bass or spruce spars.

2" blue isulation baord is also a great light wiegth scratch build material. I have a v-tail sail plane in production now using it.

THe meat trays work better than I would have ever thought! The shapes are in them for airfoils, you can get creative and make a fuse out of them. The pis next to my name is "Chicken boy". Its a scratch built from all meat trays. The fuse and tail feathers are tyson chicken trays and wing is all burgewr tray with spruce main and basswood rear spar. Very strong symetrical wing Loops in about8' rolls 2/second. Speed 300 with 350 powerdrive and a 7.2v 8 call pack. Climb out is a bit sluggish but once up, flies like crazy! Point the nose down a bit and it will get up to about 45mph!

After the pack runs out though it's comming down. Very little lift generated from the wing without the power.

Also put on a straw faux exhast and an air scoop off of a crashed Crazy sparrow to flow air accross the motor. Keeps it cooler.

Scott_nra

This was before I removed the landing gear. It was too heavy big time!

Profile shows the symetrical wing good.

Scott_nra

THis is what my symetrical wing looked like with only one layer mad up with the spars in it.

Scott_nra

I spent $119 on the Crazy Sparrow kit, crashed to peices on the first flight. I spent about $10 on Chicken Boy (mostly epoxy) and have flown it over a dozen times!

One major crash involving fooling with trims while flying and it patched up quick. If it gets nose down, you better be in control. IT will pull out in verry little space without damage but will turn into a blur before you know it going down under power!

Kind of a P-47 parkflier.

Go figure.